Brachytherapy, also known as internal radiotherapy, sealed source radiotherapy, curietherapy or endocurietherapy, is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment either permanently or temporarily. The two most common forms of brachytherapy are Low-Dose-Radiation (hereafter referred to as “LDR”) and High-Dose-Radiation (hereafter referred to as “HDR”). Prior systems, in the HDR treatment, the radioactive source is located in an afterloader machine. The afterloader machine contains a single highly radioactive pellet at the end of a wire. The pellet is pushed into each of the catheters one by one under a computer control. The computer system is operated by medical personnel who control the afterloader machine to determine the amount of time the pellet stays in each catheter and also determines the location of the pellet as predetermined by a radiation plan and radiation prescription. With a few well-placed catheters in or near the target, HDR brachytherapy can provide a very precise and effective treatment that takes only a few minutes. In contrast to LDR brachytherapy where treatment may take up 2 to 3 days or external beam radiation which can take up to 6 weeks, the HDR treatment is delivered over a period of minutes, either for a single treatment, or a plurality of treatments as prescribed by the radiation oncologist. This type of treatment has many benefits, since the afterloader controls the radiation source, and radiation exposure to the patient, doctors, and hospital staff is reduced. After the HDR treatment, the pellet retracts into the afterloader. The patient is not exposed to radiation. However, a disconcertingly larger number of misadministrations of radiation with HDR machines have been documented. Specifically, if a pellet is programmed to dwell at a position not indicated by the prescription, the patient will receive a large dose of radiation to healthy tissue and not receive any therapeutic radiation to the targeted region, and likely injuring the patient. Therefore, there is a need to have a device that can report a problem with the programming of the HDR machine. Additionally, federal and state law dictate that HDR machines must be tested every day prior to treatment, and every month. Currently, the tests are done through the use of either radiochromic film or radiographic film. Radiographic film requires the radioactive pellet to be programmed to dwell at a specific position on the film. The film is then developed, and the positional accuracy ascertained subsequently. With radiochromic film, the procedure is identical except that the film does not require development. Both quality assurance procedures incur significant costs as radiochromic film is expensive, and a film development room is expensive to maintain. Additionally, this quality assurance routine is contraindicative of the federal mandate to transition to a paperless hospital environment. Hence, there is a need in the art for a digital, cost-effective solution to the quality assurance of the HDR unit.
The afterloader machine has many different parts. Currently, the afterloader machine has a computer control, a vault, a driving system that is connected to the computer control, a plurality of connection ports that is attached to transfer tubes, and cable wires or solid metal wires. The afterloader machine has a long cable wire or solid metal wire attached to a radioactive source located inside the vault. The computer system will initiate the drive system, which is a very large motor that pushes the metal wire outside of the connection port and then into a transfer tube and eventually to a catheter inserted in a patient for irradiation. The vault is located at the base, and is the starting point from where the driving system pushes out the cable wire or solid metal wire outside the connection ports. The vault is a shielded container designed to protect individuals from radiation of the pellet while no treatment is being delivered. The computer system can push a single or multiple wires concurrently into the catheter therefore irradiating a volume. The afterloader can place a radioactive pellet within less than one millimeter accuracy, but its accuracy must be confirmed prior to patient treatments, every month, and every time maintenance operations are performed on the unit as per federal and state regulations. Since the pellet's radioactivity will decay, source changes occur every two to six months. After every source change, a large number of tests must be performed to ascertain the accuracy of the device has not been compromised. Therefore, one of ordinary skill in the art would appreciate a system that can test the pellets that have being changed in the afterloader.
Current methods in ascertaining the spatial accuracy of the radioactive pellet implement the use of radiographic or radiochromic film. In either case, the film is placed on a ruler-based jig and the radioactive pellet is sent into the jig for a predetermined time. The radiation darkens the film, which is then analyzed that the darkening is in the correct place. Both films suffer from costs (radiochromic film is expensive while radiographic film requires a film development dark room with regular maintenance). Additionally, whereas the procedure allows for a qualitative pass-fail assessment, a quantitative measurement of the accuracy of the pellet placement cannot be readily ascertained.
Government regulations such as 10 CFR Part 35, Medical Use of a Byproduct Material require facilities to test the temporal and positional accuracy of the pellet prior to patient treatments. With using radiocromic or radiographic film for testing, significant costs are incurred due to the time and equipment necessary to satisfy the mandate. Therefore, there is a need to one of ordinary skill in the art to have a testing machine that can quickly test HDR afterloader precision while reducing the cost of regulated government testing.
Also to maintain government licenses, each facility is required to produce documentation for required testing. Film inherently decomposes over time, and hence the testing record can be compromised. Additionally, film and film development equipment is expensive to obtain and to maintain, additionally, by having film as the testing device, a digital record of the testing is highly inconvenient due the necessitation of scanning the films. All these factors result in additional expenditures to maintain records and perform the necessary tests, and indirectly affect the patients' treatment costs. Therefore, one of ordinary skill in the art would appreciate a need for a digital system that conveniently stores, records and performs all the necessary testing prior to patient delivery.